This triple-blind randomized study tested whether 26.5 minutes of 26 GHz (5G) RF exposure at environmental-like levels alters salivary stress biomarkers in healthy adults. Salivary cortisol and alpha-amylase measured before, during, and after exposure did not differ between real and sham conditions. An exploratory subgroup with frequent sampling also showed biomarker stability over time. The study addresses acute exposure only and notes the need for research on repeated or long-term exposures and vulnerable groups.

This randomized, double-blind, counterbalanced provocation study tested whether short-term RF-EMF exposure alters salivary cortisol in 72 predominantly young, healthy adults. Active exposure (2 W/kg peak SAR10g in head) showed no significant effect on cortisol compared with sham, and no sex differences were observed. The authors note that results may not rule out effects in populations not studied and encourage further research into plausible biological interactions.